Clinical significance of positive platelet immunofluorescence test in thrombocytopenia

The sensitivity and specificity of the platelet immunofluorescence test for the diagnosis of idiopathic thrombocytopenia (ITP) was studied in a series of 255 patients. Patients' platelets were tested directly. Diethyl-ether eluates of these platelets and patients' sera were tested indirectly with normal donor platelets. When all three tests were considered, positive results were obtained for 92.0% of the ITP patients with a platelet count of less than 150 X 10(9)/l and for 98.4% of the patients with a count of less than 100 X 10(9)/l. However, for many patients rather weak test results were obtained, with a score of 1/2-1 in 59.8% of the patients. Most patients (94.1%) with a positive direct test had a positive indirect test on the eluate. Thus, platelet-bound antibodies but not platelet-bound immune complexes were present in most, if not all, patients. Positive immunofluorescence tests were obtained for many patients with a diagnosis other than ITP. This resulted in a low specificity of the test for the diagnosis of ITP, evidently because autoimmune thrombocytopenia occurred together with many other diseases and also because antibodies against platelet cryptantigens (expressed by the action of EDTA or by platelet fixation) were present in many patients.     

High-throughput diversity and functionality analysis of the gastrointestinal tract microbiota

The human gastrointestinal (GI) tract microbiota plays a pivotal role in our health. For more than a decade a major input for describing the diversity of the GI tract microbiota has been derived from the application of small subunit ribosomal RNA (SSU rRNA)-based technologies. These not only provided a phylogenetic framework of the GI tract microbiota, the majority of which has not yet been cultured, but also advanced insights into the impact of host and environmental factors on the microbiota community structure and dynamics. In addition, it emerged that GI tract microbial communities are host and GI tract location-specific. This complicates establishing relevant links between the host's health and the presence or abundance of specific microbial populations and argues for the implementation of novel high-throughput technologies in studying the diversity and functionality of the GI tract microbiota. Here, we focus on the recent developments and applications of phylogenetic microarrays based on SSU rRNA sequences and metagenomics approaches exploiting rapid sequencing technologies in unravelling the secrets of our GI tract microbiota.     

Liver steatosis assessment: Correlations among pathology,radiology, clinical data and automated image analysis software

Quantitating hepatic steatosis is important in many liver diseases and liver transplantation. Since steatosis estimation by pathologists has inherent intra- and inter-observer variability, we compared and contrasted computerized techniques with magnetic resonance imaging measurements, pathologist visual scoring, and clinical parameters. Computerized methods applied to whole slide images included a commercial positive pixel count algorithm and a custom algorithm programmed at our institution. For all liver samples (n = 59), including pediatric, adult, frozen section, and permanent specimens, statistically significant correlations were observed between pathology, radiology, and each image analysis modality (r = 0.75–0.97, p < 0.0001), with the strongest correlations in the pediatric cohort. Statistically significant relationships were observed between each method and with body mass index (r = 0.37–0.56, p from <0.0001 to <0.05) and with albumin (r = 0.55–0.64, p < 0.05) but not with alanine aminotransferase or aspartate aminotransferase. Although pathologist assessments correlated (r = 0.64–0.86, 0.92–0.97, and 0.78–0.91 for microvesicular, macrovesicular, and overall steatosis, respectively), the absolute values of hepatic steatosis visual assessment were susceptible to intra- and inter-observer variability, particularly for microvesicular steatosis. Image analysis, pathologist assessments, radiology measurements, and several clinical parameters all showed correlations in this study, providing evidence for the utility of each method in different clinical and research settings.